Sub-band-processing-based clutter suppression method and apparatus for passive radar

Abstract

The invention discloses a sub-band-processing-based clutter suppression method and apparatus for a passive radar. The method comprises the four steps of sub band decomposition, over-sampling clutter sub space construction, LS adaptive filtering, and sub band synthesis. To be specific, a monitoring signal is composed into multi-path sub band signals; a clutter sub space is constructed in an over sampling mode by using a reference signal; sub band decomposition is carried out; LS adaptive filtering is carried out on each sub band; and then the filtered sub band signals are synthesized to obtain a monitoring signal after clutter suppression. According to the method, the robustness on non-ideal factors like a carrier frequency offset, a sampling rate frequency offset, a fractional delay, and a channel frequency response and the like is high; the clutter suppression performance is close to the theoretical upper limit; the calculation load is low; the parallel processing architecture is provided; and thus the method and apparatus are suitable for engineering real-time implementation and have the popularization and application values.

Description

technical field [0001] The invention relates to the technical field of external radiation source radar signal processing, in particular to a method and device for suppressing external radiation source radar clutter based on subband processing. Background technique [0002] External radiation source radar is a non-cooperative bistatic / multistatic radar system built on the basis of external radiation sources. Because the emission signal is unknown, two types of channels are often set in the external radiation source radar, namely the reference channel and the monitoring channel. The reference channel is used to collect the transmitted signal, and the purified reference signal is used as a reference and matching sample; the monitoring channel is used to receive the target scattering signal, and the channel output is called the monitoring signal. The direct path signal from the transmitting station to the receiving station is called a direct wave. Under ideal conditions, it is ...

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Problems solved by technology

However, there are significant differences between the subband clutter cancellation method of the present invention and the frequency domain ECA-B method in the core steps of clutter cancellation, specifically shown in: 1) The subband clutter cancellation method adopts frequency offset subspace expansion and delay subspace expansion are used to eliminate the adverse effects of non-ideal factors such as carrier frequency offset and fractional delay, but the frequency domain ECA-B method does not specifically consider this point; 2) The subband clutter cancellation method uses LS adaptive filtering To cancel clutter, LS adaptive filtering is related to the construction of oversampled clutter subspace, which is also different from the cancellation method in the frequency domain ECA-B method

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